Various progress, doesnt compile

Added prelude, made lambdas a single-token prefix like NS, made progress on implementations, removed const line type

orchid-api/src/tree.rs

@@ -27,7 +27,7 @@ pub struct TokenTree {
 #[derive(Clone, Debug, Coding)]
 pub enum Token {
 	/// Lambda function head, from the opening \ until the beginning of the body.
-	LambdaHead(Vec<TokenTree>),
+	LambdaHead(Box<TokenTree>),
 	/// A name segment or an operator.
 	Name(TStr),
 	/// A newly generated expression. The last place this is supposed to happen is